It is common practice to provide a power brush for the treatment of a surface, e.g. to clean the latter or apply a particular texture thereto, for polishing or a similar purpose. An example of the use of such power brushes is in a vacuum cleaner for automatic or industrial purposes, or in a street-cleaning machine. However, power brushes are also used in floor washing operations independently of the application of suction.
In the past, the brushes employed have generally been of one of two types.
In one of these types, the bristles project radially from an elongated rotating support such as a shaft or drum and the brush is rotated about the axis with respect to which the bristles project radially. The brush is moved across the surface to be treated in a direction transverse to the axis and the brushing effectiveness is generally a function of the relationship between the downward force applied to the brush, the rate of rotation of the latter, the speed with which the brush is moved across the surface and, of course, the number and character of the bristles which project radially.
One of the drawbacks of this type of brushing action is that each bristle tends to meet the surface in the same way as each other bristle, i.e. each bristle is effectively rotated in its plane perpendicular to the axis and thus describes a circular pattern of movement, encountering the surface in the same direction upon each revolution.
In the other principal type of brush, a bristle carrier, e.g. a disk, is rotated about its axis and the bristles project from this disk generally in the axial direction with possible a convergence or a divergence to or from the axis. The bristles extend generally transversely to the surface, generally contact the latter at their tips, and are moved in a radial direction, the axis being upright.
Each bristle, therefore, sweeps the surface in a circular path and as the brush is moved over the surface, the circular paths of the multitude of bristles overlap and provide an effective brushing action. Notwithstanding the overlap of the circular pattern of movement of the bristles on each disk, however, as the bristles move through, for example, the nap of a carpet, they tend to displace the nap in the same direction so that ultimately the tufts of carpet are wiped in only one direction with each pass of the brush. This has drawbacks in carpet shampooing and, in general, this type of scrubbing action has been found to be less than satisfactory in many cases.
In my aforementioned copending application and the patent which has issued on its parent applicant, I have described a unique rake which can be used for soil cultivation and, indeed, for the preparation of the soil in place of plowing and like procedures, exploiting movable tines which automatically reposition themselves as a support for the tines is given an orbital or cyclical motion. This results in a unique pattern of movement of the tines with respect to the ground and has been found to break up more effectively than heretofore soil clumps, clods and the like.
I have now found that a similar pattern of movement can be utilized effectively in a power brush, especially in vacuum cleaner and like applications.